Electrical switches which can be made operative by contact with water are broadly known. However, the water sensitive electrical switches of the prior art are not fully satisfactory, especially for applictions for controlling the automatic inflation of flotation equipment when dumped into water. Inflatable equipment, such as a life vest or life raft, must be capable of being stored in a deflated condition for long periods of time and is only called upon in emergency situations. However, when such a situation arises it is most important that operation of the electrical switch to control inflation is assured.
Some prior art devices were battery operated but due to long standby the battery would deteriorate or would be ineffective to produce sufficient electrical energy, especially under low temperature conditions. Moreover, some prior art devices were complicated or of relatively large size and weight, or were too sensitive so that the electrical switch would actuate undesirably when the ambient relative humidity was high or the device was inadvertently splashed with water.